Koulev, Soul of the Grave

Deathtouch
Koulev, Soul of the Grave doesn't untap during
your untap step.
{3}{b}{b}, {t}, Creatures your opponents control get
-X/-X until end of turn, where X is the number
of Black creatures in your graveyard.
Sacrifice a creature: Untap Koulev, Soul of the
Grave.